RU2729701C1 - Cellulose composition with ability to eliminate unpleasant odour - Google Patents

Abstract

FIELD: pulp industry.SUBSTANCE: invention relates to fluff pulp with improved ability to eliminate unpleasant odour, as well as methods for production of fluff pulp. Fluff pulp contains bleached kraft fibre having weighted average fibre length of about 2 mm, copper number of less than about 7, carboxyl group content of more than about 3.5 meq/100 g, whiteness by ISO of at least 80, viscosity from about 2 cP to about 9 cP, and content of copper ions from about 0.2 parts per million to about 50 parts per million in terms of weight of bleached kraft fibre.EFFECT: technical result is improved ability to eliminate unpleasant smell of fluff pulp.26 cl, 4 tbl

Description

The technical field to which the present invention relates

[0001] The present technology generally relates to fluff pulps with improved odor control properties, as well as methods for making such fluff pulps.

Summary of the present invention

[0002] In one aspect, there is provided a fluff pulp that contains bleached kraft fiber and has a copper ion content of about 0.2 ppm to about 50 ppm based on the weight of bleached kraft fiber. The bleached kraft fiber has a weighted average fiber length of at least about 2 mm, a copper number of less than about 7, a carboxyl content of more than about 3.5 meq / 100 g; an ISO brightness of at least 80 and a viscosity of about 2 cps to about 9 cps, and wherein the fluff has a copper ion content of about 0.2 ppm to about 50 ppm, based on the weight of the bleached kraft fiber.

[0003] In a related aspect, there is provided a method for producing cellulose fluff. The method includes treating a lignocellulosic material by adding, based on the weight of the lignocellulosic material, from about 50 ppm to about 200 ppm catalyst consisting of a combination of copper and iron or their salts in the presence of about 0.5% to about 5% oxidizing agent, based on the weight of the lignocellulosic material, to obtain the treated lignocellulosic material. In the process, the weight ratio of iron and iron salts to copper and copper salts is at most about 10: 1. The treated lignocellulosic material has a viscosity of from about 2 cps to about 6 cps and has at least 50% greater inhibitory effect on ammonia formation than the second treated lignocellulosic material formed by the same method but in the absence of copper. The lignocellulosic material can be a lignocellulosic kraft stock, such as a lignocellulosic kraft stock that has been bleached with chlorine dioxide.

[0004] In any embodiment of this document, the method may comprise treating the lignocellulosic kraft stock by adding, based on the weight of the lignocellulosic kraft stock, from about 50 ppm to about 200 ppm catalyst in the presence of about 0.5% up to about 5% of an oxidizing agent, based on the weight of the lignocellulosic kraft mass at acidic pH, to obtain a treated lignocellulosic material.

[0005] In any embodiment of this document, the method may include treating the lignocellulosic kraft stock by adding, based on the weight of the lignocellulosic kraft stock, from about 50 ppm to about 150 (or about 200) ppm catalyst in the presence of from about 0.5% to about 5% oxidizing agent, based on the weight of the lignocellulosic kraft mass, at a pH of about 2.5 to about 5 to provide a treated lignocellulosic material; where the lignocellulosic kraft mass is in an aqueous solution of about 8 wt. % to about 12 wt. % lignocellulose kraft mass, taking into account water in solution; the weight ratio of iron and iron salts to copper and copper salts is from about 8: 1 to about 1: 8; and the treated lignocellulosic material has a viscosity of from about 3 cps to about 5 cps.

[0006] In a further related aspect, there is provided a method of improving the odor control properties of fluff pulp. The method includes treating a first lignocellulosic material by adding from about 3.5 ppm to about 200 ppm copper salt and from about 25 ppm to about 175 (or about 196.5) ppm iron salt at a pH of about 1 to about 9 to form a second lignocellulosic material, the weight ratio of iron salt to copper salt being from about 8: 1 to about 1: 1; wherein the dry second lignocellulosic material has at least 50% greater inhibitory effect on ammonia formation than the dry first lignocellulosic material.

Detailed Disclosure of the Present Invention

I. Definitions

[0007] The following terms are used throughout the text, as defined below.

[0008] As used herein and in the appended claims, the singular in the context of describing the elements (particularly in the context of the following claims) is to be construed as encompassing both the singular and the plural, unless otherwise indicated herein, or clearly does not contradict the context. Specification of ranges of values in this document is intended only as a quick way of recording references separately for each individual value falling within the range, unless otherwise indicated in this document, and each individual value is included in the description as if it were separately indicated in this document ... All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any or all of the examples or an introductory word before an example (eg, "such as") provided herein is intended only to better illuminate the embodiments and is not intended to limit the scope of the claims unless otherwise indicated. Nothing in the description should be construed as indicating any undeclared element as important.

[0009] When used herein, "approximately" will be understood by those of skill in the art and will vary somewhat depending on the context to which it is used. If there are uses of the term that are not clear to a person skilled in the art given the context in which it is used, “about” will mean up to plus or minus 10% of a particular indicator.

[0010] As will be understood by one of ordinary skill in the art, for any and all purposes, especially with respect to providing a written description, all ranges disclosed herein also encompass any and all possible sub-ranges and combinations of sub-ranges. Any specified range can be easily defined as sufficiently described and allowing the same range to be subdivided into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein can be easily divided into lower third, middle third and upper third, etc. The person skilled in the art will also understand that all expressions such as "before", "at least", "more", "less" and the like, include the specified the number and refer to ranges, which can then be subdivided into sub-ranges as discussed above. Finally, one skilled in the art will understand that the range includes every single term. Thus, for example, a group containing 1 to 3 atoms refers to groups containing 1, 2 or 3 atoms. Likewise, a group containing 1-5 atoms refers to groups containing 1, 2, 3, 4 or 5 atoms, etc.

[0011] The term "halide" as used herein refers to bromide, chloride, fluoride, or iodide.

II. Technology of the present invention

[0012] Pulp has been used in various absorbent personal care or health care products such as diapers or incontinence hygiene products. However, odor caused by bodily fluids is a major problem, such as ammonia odor from urine in a diaper case. For other applications, foul odor can be caused by other nitrogenous or sulfur-containing substances.

[0013] The technology of the present invention is directed to fluff pulps that have improved odor control properties, as well as methods for making such effective fluff pulps. The fluff pulps are characterized by significantly improved odor control properties, at least in part due to the use of unexpectedly low amounts of copper. While particularly suitable for diapers or incontinent hygiene products, the technology of the present invention applies to any situation where the ability to eliminate unpleasant odor is beneficial and / or preferred.

[0014] Thus, in an aspect, there is provided a fluff pulp that contains bleached kraft fiber and has a copper ion content of from about 0.2 ppm to about 50 ppm, based on the weight of bleached kraft fiber. The bleached kraft fiber has a weighted average fiber length of at least about 2 mm, a copper number of less than about 7, a carboxyl content of more than about 3.5 meq / 100 g; an ISO brightness of at least 80; and a viscosity of about 2 cps to about 9 cps. The cellulose fluff may or may not contain a superabsorbent polymer (SAP) such as sodium polyacrylate polymers and copolymers. Kraft fiber can be made from softwood fibers, hardwood fibers, or mixtures thereof, such fibers being described in more detail herein.

[0015] As described later in this document and among other features of fluff pulp, it was surprisingly found that the inclusion of copper ions in an amount of from about 0.2 ppm to about 50 ppm copper based on the weight of bleached kraft fiber significantly improves odor control properties compared to fluff pulp that does not contain copper. Of course, significant odor control properties would not be expected by one skilled in the art from the inclusion of such a low copper ion content.

[0016] The fluff pulp may have at least 50% greater inhibitory effect on ammonia formation than a second fluff pulp with the same characteristics but no copper, ie. fluff pulp of the same composition, except for the fact that copper ions are not included in the fluff pulp. The "inhibitory effect on ammonia formation" is where the fluff has less ammonia gas as determined in the tests of Example 1 (where SAP is not present) and / or Example 2 (where SAP is present) compared to fluff of the same composition, except the fact that copper ions are not included in the fluff pulp. Without limiting by any theory, it is believed that this inhibitory effect may be due to increased absorption of NH ₃ in the fluff pulp, prevention of conversion of nitrogenous substances to NH ₃ , or a combination of both. The inhibitory effect can be at least about 50% more, at least about 55% more, at least about 60% more, at least about 65% more, at least about 70% more, by at least about 75% more, at least about 80% more, at least about 85% more, at least about 90% more, at least about 92% more, at least about 94 % more, at least about 96% more, at least about 98% more, at least about 99% more, about 100% more, or in any range including and / or between any two of these values.

[0017] Copper ions from the contained copper ions can be associated with bleached kraft fiber and / or can be in the form of a copper (I) salt, copper (II) salt, hydrates thereof, or a combination of any two or more of them. Copper (I) salts include, but are not limited to, copper (I) chloride, copper (I) oxide, copper (I) sulfate, or a combination of any two or more of these. Copper (II) salts include, but are not limited to, copper (II) carbonate, copper (II) chloride, copper (II) phosphate, copper (II) nitrate, copper (II) perchlorate, copper (II) phosphate, copper (II) sulfate ), copper (II) tetrafluoroborate, copper (II) triflate, or combinations of any two or more of them. A ligand for non-kraft fiber and copper and / or its salts may be included in the fluff pulp, where such ligands include, but are not limited to, ethylenediaminetetraacetic acid, (S, S ') - ethylenediamine-N, N'-disuccinic acid , diethylenetriaminepentaacetic acid, ethylene glycol bis (2-aminoethyl) -N, N, N ', N'-tetraacetic acid, trans-1,2-diaminocyclohexanetetraacetic acid, or mixtures of any two or more thereof. A non-kraft fiber ligand may not be included in the fluff pulp. Unlike a non-kraft fiber ligand, a "kraft fiber ligand" is a fragment or part of a kraft fiber.

[0018] The copper ion content of the fluff pulp, based on the weight of the bleached kraft fiber, may be about 0.2 ppm, about 0.5 ppm, about 1 ppm, about 2 ppm , about 3 ppm, about 4 ppm, about 5 ppm, about 6 ppm, about 7 ppm, about 8 ppm, about 9 ppm, about 10 ppm, about 12 ppm, approximately 14 ppm, approximately 16 ppm, approximately 18 ppm, approximately 20 ppm, approximately 22 ppm, approximately 24 ppm, approximately 26 ppm, approximately 28 ppm ppm, about 30 ppm, about 32 ppm, about 34 ppm lyon, about 36 ppm, about 38 ppm, about 40 ppm, about 42 ppm, about 44 ppm, about 46 ppm, about 48 ppm, about 50 ppm, as well as any range including and / or between any two of these values. Copper ion content can be determined by conventional analytical methods such as ICP (Inductively Coupled Plasma) -Atomic Absorption. Thus, this value for the content of copper ions refers to the mass quantity of the Cu ⁺¹ ions themselves and / or the Cu ⁺² ions as opposed to the total mass quantity of copper salts (for example, the total mass quantity of copper sulfate). As a further example, the weight amount of copper ions in copper sulfate is about 0.4 of the total weight amount of copper sulfate.

[0019] The fluff pulp may also contain iron ions or may not. The iron ions associated with bleached kraft fiber can be in the form of ferrous salts (Fe ²⁺ ), ferric salts (Fe ³⁺ ), their hydrates, and combinations of any two or more of these. Ferrous salts and / or ferric salts include halide, sulfate, nitrate, phosphate, carbonate, and combinations of any two or more of these. Examples include, but are not limited to, ferrous sulfate (e.g., ferrous sulfate heptahydrate), ferrous chloride, ferrous ammonium sulfate, ferric chloride, ferric ammonium double sulfate, or ferric ammonium double citrate. The amount of iron ions (“iron ion content”) in the fluff pulp can range from about 0.2 ppm to about 50 ppm, based on the weight of the bleached kraft fiber; thus, the amount of iron ions, based on the weight of the bleached kraft fiber, can be about 0.2 ppm, about 0.5 ppm, about 1 ppm, about 2 ppm, about 3 ppm, about 4 ppm, about 5 ppm, about 6 ppm, about 7 ppm, about 8 ppm, about 9 ppm, about 10 ppm, about 12 ppm, about 14 ppm, about 16 ppm, about 18 ppm, about 20 ppm, about 22 ppm, about 24 ppm, about 26 ppm, about 28 ppm, about 30 ppm million, about 32 ppm, about 34 ppm, about 36 ppm ppm, about 38 ppm, about 40 ppm, about 42 ppm, about 44 ppm, about 46 ppm, about 48 ppm, about 50 ppm, or any range including and / or between any two of these values. Iron content can be determined by conventional analytical methods such as ICP atomic absorption.

[0020] As discussed previously, the bleached kraft fiber has a weighted average fiber length of at least about 2 mm. The bleached kraft fiber may have a weighted average fiber length of about 2 mm, about 2.1 mm, about 2.2 mm, about 2.3 mm, about 2.4 mm, about 2.5 mm, about 2.6 mm, about 2.7 mm, approximately 2.8 mm, approximately 2.9 mm, approximately 3.0 mm, approximately 3.1 mm, approximately 3.2 mm, approximately 3.3 mm, approximately 3.4 mm, approximately 3, 5 mm, approximately 3.6 mm, approximately 3.7 mm, approximately 3.8 mm, approximately 3.9 mm, approximately 4.0 mm, or any range greater than any one of these values, or any range including and / or between any two of these values. Such weighted average fiber length can be determined with the Fiber Quality Analyzer ™ from OPTEST, Hawkesbury, Ontario, following the manufacturer's standard procedures.

[0021] The bleached kraft fiber has a copper number of less than about 7. This copper number can be measured according to TAPPI T430-cm99. The bleached kraft fiber may have a copper number of about 1, about 2, about 3, about 4, about 5, about 6, about 7, or any range less than any one of these values, or any range including and / or between any two of these values. The bleached kraft fiber also has a carboxyl content of more than about 3.5 meq / 100 g, where the carboxyl content can be measured according to TAPPI T237-cm98. Thus, the carboxyl group content (in meq / 100 g) of the bleached kraft fiber can be about 3.6, about 3.8, about 4.0, about 4.5, about 5, about 5.5, about 6, about 6.5, about 7, about 7.5, about 8, or any range including and / or between any two of these values. Carboxyl content can be measured according to TAPPI T237-cm98.

[0022] The bleached kraft fluff pulp has an ISO brightness of at least 80. ISO whiteness can be determined according to TAPPI T525-om02. The ISO whiteness of bleached kraft fiber can be 80, about 82, about 84, about 86, about 88, about 90, about 91, about 92, about 93, about 94, about 95, or any range including and / or between any two of these values. In any embodiment of the present document, the bleached kraft fiber may be free of optical brighteners. In any embodiment of the present document, the cellulose fluff may be free of optical brighteners.

[0023] As previously indicated herein, the bleached kraft fluff pulp has a viscosity of from about 2 cps to about 9 cps. The viscosity of bleached kraft fiber can be determined according to the TAPPI T230-om99 procedure. Thus, the viscosity of the bleached kraft fiber can be about 2, about 2.5, about 3, about 3.5, about 4, about 4.5, about 5, about 5.5, about 6, about 6.5, about 7, about 7.5, about 8, about 8.5, about 9, or any range including and / or between any two of these values.

[0024] In a related aspect, a method for producing cellulose fluff is provided. The method involves treating a lignocellulosic material by adding, based on the weight of the lignocellulosic material, from about 50 ppm to about 200 ppm of a catalyst consisting of a combination of copper and / or its salts and iron and / or its salts in the presence of about 0 , 5% to about 5% oxidizing agent, based on the weight of the lignocellulosic material, to obtain the treated lignocellulosic material. In the process, the weight ratio of iron and iron salts to copper and copper salts is at most about 10: 1. The treated lignocellulosic material has a viscosity of from about 2 cps to about 6 cps and has at least 50% greater inhibitory effect on ammonia formation than the second treated lignocellulosic material formed by the same process in the absence of copper. The inhibitory effect can be at least about 50% more, at least about 55% more, at least about 60% more, at least about 65% more, at least about 70% more, by at least about 75% more, at least about 80% more, at least about 85% more, at least about 90% more, at least about 92% more, at least about 94 % more, at least about 96% more, at least about 98% more, at least about 99% more, about 100% more, or in any range including and / or between any two of these values.

[0025] The lignocellulosic material may preferably be wood pulp. The lignocellulosic material can be in the form of fibers and / or particles, such as cellulose fibers, fine particles and / or other fragments of cellulose, hemicellulose, starch and / or polysaccharide particles and powders. The lignocellulosic material may also contain cellulose derivatives such as carboxymethyl cellulose, hydroxypropyl cellulose and the like. Suitable lignocellulosic materials include, but are not limited to, those obtained from known sources of such materials, such as plants. Illustrative suitable lignocellulosic materials are polysaccharides, such as starches, as described in US Pat. No. 8,007,635, incorporated by reference herein. Exemplary lignocellulosic materials for use in the methods described in any embodiment of this document are cellulose fibers used in fabrics, towels, diapers, feminine hygiene products, and adult incontinence products and used to make other types of cellulosic products, paper and / or cardboard. Such cellulosic fibers include those derived from deciduous trees, conifers, or a combination of deciduous and coniferous trees, obtained for use in papermaking by any known suitable fermentation, refining and / or bleaching operations such as, for example, known mechanical, thermomechanical, chemical and semi-chemical and other pulping processes; and other pulping processes known to those skilled in the art. The term “hardwood pulp” as used herein refers to pulp obtained from woody matter of deciduous trees (angiosperms), while “softwood pulp” is pulp obtained from woody matter of coniferous trees (gymnosperms). Suitable cellulosic fibers can be obtained from non-woody herbaceous plants, including but not limited to kenaf, hemp, jute, flax, sisal and / or abaca, although legal restrictions and other considerations may make the use of hemp and other fiber sources impractical or impossible. Either bleached or unbleached cellulosic fibers such as unbleached kraft and bleached kraft (collectively referred to as “lignocellulosic kraft”) and / or waste paper can be used in any embodiment of the methods described herein. The pulp could have been previously subjected to any processing that is common in pulping and bleaching, or it can be specially modified, for example, by controlled pre-hydrolysis and / or alkaline treatment of the chips before kraft pulping, acidic and / or enzymatic (for example, cellulase and / or hemicellulase) by hydrolysis of kraft mass and / or alkaline treatment of the mass with washing with cold water (for mercerization).

[0026] "Copper and / or its salts" refers to elemental copper (Cu °), copper (I) salt, copper (II) salt, hydrates thereof, or a combination of any two or more of them. Copper (I) salts include, but are not limited to, copper (I) chloride, copper (I) oxide, copper (I) sulfate, or a combination of any two or more of these. Copper (II) salts include, but are not limited to, copper (II) carbonate, copper (II) chloride, copper (II) phosphate, copper (II) nitrate, copper (II) perchlorate, copper (II) phosphate, copper (II) sulfate ), copper (II) tetrafluoroborate, copper (II) triflate, or combinations of any two or more of them. In any embodiment of this document, the amount of added copper and / or its salts may be from about 3.5 ppm to about 199.8 ppm, based on the weight of the lignocellulosic material; thus, the amount of added copper or its salts can be about 3.5 ppm, about 4 ppm, about 4.5 ppm, about 5 ppm, about 5.5 ppm, about 6 ppm ppm, about 7 ppm, about 8 ppm, about 9 ppm, about 10 ppm, about 12 ppm, about 14 ppm, about 16 ppm, about 18 ppm , about 20 ppm, about 22 ppm, about 24 ppm, about 26 ppm, about 28 ppm, about 30 ppm, about 32 ppm, about 34 ppm, about 36 ppm, approximately 38 ppm, approximately 40 ppm, approx about 42 ppm, about 44 ppm, about 46 ppm, about 48 ppm, about 50 ppm, about 55 ppm, about 60 ppm, about 65 ppm, about 70 ppm, about 75 ppm, about 80 ppm, about 85 ppm, about 90 ppm, about 95 ppm, about 100 ppm, about 120 ppm, about 140 ppm million, about 160 ppm, about 180 ppm, about 190 ppm, about 199.8 ppm, about 200 ppm, or any range including and / or between any two of these values.

[0027] "Iron and / or its salts" refers to elemental iron (Fe °), ferrous salts (Fe ²⁺ ), ferric salts (Fe ³⁺ ), hydrates thereof, and combinations of any two or more of them. Preferred ferrous salts and / or ferric salts include halide, sulfate, nitrate, phosphate, carbonate, and combinations of any two or more thereof. Examples include, but are not limited to, ferrous sulfate (e.g., ferrous sulfate heptahydrate), ferrous chloride, ferrous ammonium sulfate, ferric chloride, ferric ammonium double sulfate, or ferric ammonium double citrate. In any embodiment of this document, the amount of added iron or its salts may be from about 0.2 ppm to about 180 ppm, based on the weight of the lignocellulosic material; thus, the amount of iron or its salts added can be about 0.2 ppm, about 0.5 ppm, about 1 ppm, about 2 ppm, about 3 ppm, about 4 ppm , about 5 ppm, about 6 ppm, about 7 ppm, about 8 ppm, about 9 ppm, about 10 ppm, about 12 ppm, about 14 ppm, about 16 ppm, about 18 ppm, about 20 ppm, about 22 ppm, about 24 ppm, about 26 ppm, about 28 ppm, about 30 ppm, about 32 ppm per million, approximately 34 ppm, approximately 36 ppm, approximately but 38 ppm, approximately 40 ppm, approximately 42 ppm, approximately 44 ppm, approximately 46 ppm, approximately 48 ppm, approximately 50 ppm, approximately 55 ppm, approximately 60 ppm, about 65 ppm, about 70 ppm, about 75 ppm, about 80 ppm, about 85 ppm, about 90 ppm, about 95 ppm, about 100 ppm million, about 120 ppm, about 140 ppm, about 160 ppm, about 180 ppm, or any range including and / or between any two of these values.

[0028] In the process, the weight ratio of iron and iron salts to copper and copper salts is at most about 10: 1. By "at most about 10: 1" is meant that no greater ratio of iron and iron salts to copper and copper salts is included, such as 11: 1, but does not include a range where iron is not included, since then there will be no ratio at all. The weight ratio of iron and iron salts to copper and copper salts can be about 10: 1, about 9: 1, about 8: 1, about 7: 1, about 6: 1, about 5: 1, about 4: 1, about 3 : 1, approximately 2: 1, approximately 1: 1, approximately 1: 2, approximately 1: 3, approximately 1: 4, approximately 1: 5, approximately 1: 6, approximately 1: 7, approximately 1: 8, approximately 1 : 9, approximately 1:10, or any range including and / or between any two of these values.

[0029] The oxidizing agent may include one or more of hydrogen peroxide, chlorine dioxide, hypochlorite, and hypochlorous acid. Preferred oxidizing agents contain hydrogen peroxide. The amount of oxidizing agent is from about 0.5% to about 5% of the oxidizing agent, based on the weight of the lignocellulosic material; thus, the amount of oxidizing agent can be about 0.5%, about 0.6%, about 0.7%, about 0.8%, about 0.9%, about 1%, about 1.2%, about 1 , 4%, about 1.6%, about 1.8%, about 2%, about 2.2%, about 2.4%, about 2.6%, about 2.8%, about 3%, about 3 , 2%, about 3.4%, about 3.6%, about 3.8%, about 4%, about 4.2%, about 4.4%, about 4.6%, about 4.8%, approximately 5%, or any range including and / or between any two of these values.

[0030] The catalyst can be added in the presence of an oxidizing agent based on the weight of the lignocellulosic material at a pH of from about 1 to about 9. The treatment pH can vary widely and any temperature can be used sufficient to produce the desired treated lignocellulosic material. The pH of the treatment can be about 1.0, about 1.5, about 2.0, about 2.5, about 3.0, about 3.5, about 4.0, about 4.5, about 5.0, about 5.5, about 6.0, about 6.5, about 7.0, about 7.5, about 8.0, about 8.5, about 9.0, or any range including and / or between any two of these values. For example, the pH can be an acidic pH (i.e., about 1 to less than about 7), and the pH can preferably be from about 2 to about 6, and more preferably from about 2.5 to about 5.

[0031] When the amount of another component is determined on a weight basis, for example of a lignocellulosic material, it is expressed on a dry weight basis of the lignocellulosic material. Lignocellulosic material (for example, lignocellulosic kraft mass) can be in an aqueous solution in an amount of about 8 wt. % to about 16 wt. % of lignocellulosic material, taking into account water in solution. Thus, the lignocellulosic material can be about 8 wt. %, approximately 9 mass. %, approximately 10 mass. %, approximately 11 mass. %, approximately 12 mass. %, approximately 13 mass. %, approximately 14 mass. %, approximately 15 mass. %, approximately 16 mass. % or any range including and / or between these values.

[0032] The processing temperatures can vary widely, and any temperature can be used that is sufficient to produce the desired processed lignocellulosic product. The processing temperature is usually at least about 20 ° C, although lower temperatures can be used if they are effective to obtain the desired lignocellulosic material. The processing temperature may be approximately 20 ° C, approximately 40 ° C, approximately 50 ° C, approximately 60 ° C, approximately 65 ° C, approximately 70 ° C, approximately 75 ° C, approximately 80 ° C, approximately 85 ° C, approximately 90 ° C, about 95 ° C, about 100 ° C, about 110 ° C, about 120 ° C, or any range including and / or between any two of these values. The processing temperature is preferably from about 40 ° C to about 120 ° C, even more preferably from about 40 ° C to about 90 ° C, and most preferably from about 65 ° C to about 90 ° C.

[0033] The processing time can vary widely, and any time can be used that is sufficient to obtain the desired processed lignocellulosic product. The processing time is usually at least about 5 minutes, although longer processing can be used if it is effective to obtain the desired lignocellulosic material. The processing time is preferably from about 5 minutes to about 20 hours, more preferably from about 15 minutes to about 10 hours, and even more preferably from about 30 minutes to about 4 hours. Suitable processing times include approximately 5 minutes, approximately 10 minutes, approximately 30 minutes, approximately 1 hour, approximately one and a half hours, approximately 2 hours, approximately 3 hours, approximately 4 hours, approximately 6 hours, approximately 8 hours, approximately 10 hours, approximately 15 hours, approximately 20 hours, or any range including and / or between any two of these values.

[0034] Optionally, the method may or may not be carried out in the presence of UV radiation besides the catalyst and oxidizing agent, and it is preferred when hydrogen peroxide is used as the oxidizing agent. The inclusion of UV radiation has the advantage of being more effective at lower temperatures such as room temperature (or ambient temperature) without the need for heating equipment and can be used to extend the effective pH range. For example, the method can be effectively carried out in the presence of UV radiation at ambient temperature (or without heating) at approximately neutral pH (i.e., from about 6.8 to about 7.2) and / or for a very short time from several seconds to approximately 1 hour, depending for example on the power of the UV lamp. The UV lamp used in the method is preferably a high intensity lamp such as a medium pressure mercury arc lamp or a variant thereof, a xenon flash lamp, or an excimer lamp. Most preferred is the use of a medium pressure mercury arc lamp, which is low cost and readily available in the market. One or more UV lamps, which are usually embedded in quartz casings, can be inserted (submerged) in the mass to be emitted. It may sometimes be preferable to place the UV lamps over the agitated suspension of lignocellulosic material. For this type of UV radiation, both mercury arc lamps and electrodeless lamps (such as those from Fusion UV) can be used. It is preferable that the mass is completely miscible and well mixed during the reaction, since the penetration of UV radiation into water is very low and most of the chemical attack is due to the UV decomposition of the peroxide in aqueous solutions. In any embodiment of this document, UV treatment may or may not be performed with the addition of a UV catalyst. Suitable UV catalysts include, but are not limited to, micro- or nanoparticle photocatalysts based on titanium dioxide or zinc oxide; water-soluble organic catalyst based on azo compounds such as 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2-methylpropionamidine) dihydrochloride, 2,2'-azobis (2-methylpropionitrile) (AIBN ), 1,1'-azobiscyclohexanecarbonitrile (e.g., VAZO® 88 catalyst from DuPont) and / or (2,2,6,6-tetramethylpiperidinyl) oxyl (TEMPO).

[0035] The method can be carried out in batch, continuous, or semi-continuous mode. The process can also be practiced as part of a pulping process as a process step at the end of a mechanical, semi-chemical or chemical pulping process, or as part of a multi-stage bleaching process as a step at the end of a bleaching process (i.e., no more bleaching steps are carried out after the process step ). The method can also be used to treat market pulp for paper and / or fluff pulp, for example by re-coarse washing of market pulp for paper or fluff pulp in a pulper or the like. Treatment in a pulper or the like has flexibility in terms of controlling conditions. For example, the treatment can begin at an acidic pH, and after some suitable period of time, the treatment comprises adjusting to an alkaline pH by adding alkali and continuing the reaction at a higher pH. This combined acid-base treatment can be used to alter the ratio of carboxyl and carbonyl groups in the treated lignocellulosic material.

[0036] The treated lignocellulosic material can have any one or more of the features previously described for fluff pulp (e.g., a weight average length of at least about 2 mm, a copper number of less than about 7, a carboxyl content of more than about 3.5 meq / 100 d; an ISO brightness of at least 80 and a viscosity of about 2 cps to about 9 cps, or a combination of any two or more of them), as well as any range described herein. In any embodiment of the present invention, and as previously discussed for fluff pulp, the treated lignocellulosic material may have a copper ion content of from about 0.2 ppm to about 50 ppm, based on the weight of the treated lignocellulosic material, or any range of copper ion content. described in this document. In any embodiment of the present invention, and as previously discussed for fluff pulp, the treated lignocellulosic material may have an iron ion content of from about 0.2 ppm to about 50 ppm, based on the weight of the treated lignocellulosic material.

[0037] In a further related aspect, there is provided a method for improving the odor control properties of fluff pulp, the method comprising treating a first lignocellulosic material by adding from about 0.5 ppm to about 200 ppm copper salt at a pH of about 1 to about 9 to form a second lignocellulosic material, wherein the dry second lignocellulosic material has at least 50% greater inhibitory effect on ammonia formation than the dry first lignocellulosic material. The inhibitory effect can be at least about 50% more, at least about 55% more, at least about 60% more, at least about 65% more, at least about 70% more, by at least about 75% more, at least about 80% more, at least about 85% more, at least about 90% more, at least about 92% more, at least about 94 % more, at least about 96% more, at least about 98% more, at least about 99% more, about 100% more, or in any range including and / or between any two of these values. The pH can be about 1.0, about 1.5, about 2.0, about 2.5, about 3.0, about 3.5, about 4.0, about 4.5, about 5.0, about 5 , 5, approximately 6.0, approximately 6.5, approximately 7.0, approximately 7.5, approximately 8.0, approximately 8.5 approximately 9.0, or any range including and / or between any two of these values.

[0038] In any embodiment of such a method of the present document, the first lignocellulosic material may not contain more than about 0.2 ppm copper, preferably not more than about 0.1 ppm copper, even more preferably not more than about 0, 01 ppm copper. In any embodiment of the present invention, the first lignocellulosic material may be free of detectable copper as measured by ICP atomic absorption.

[0039] Copper salts are previously described and the term "copper salt" should mean one copper salt, a mixture of any two or more copper salts, a hydrate of any one or more of the preceding ones, and a combination of any two or more of them, where the amount of added copper salts can be about 0.5 ppm, about 0.6 ppm, about 0.7 ppm, about 0.8 ppm, about 0.9 ppm, about 1.0 ppm million, about 1.2 ppm, about 1.4 ppm, about 1.6 ppm, about 1.8 ppm, about 2.0 ppm, about 2.5 ppm, about 3.5 ppm, about 4 ppm, about 4.5 ppm, about 5 ppm, about 5.5 ppm, about 6 ppm, about 7 ppm, about 8 h astey per million, approximately 9 ppm, approximately 10 ppm, approximately 12 ppm, approximately 14 ppm, approximately 16 ppm, approximately 18 ppm, approximately 20 ppm, approximately 22 ppm million, about 24 ppm, about 25 ppm, about 26 ppm, about 28 ppm, about 30 ppm, about 32 ppm, about 34 ppm, about 36 ppm, about 38 ppm, about 40 ppm, about 42 ppm, about 44 ppm, about 46 ppm, about 48 ppm, about 50 ppm, about 55 ppm, about 60 ppm, approximately 65 ppm, approximately 70 hours teas per million, approximately 75 ppm, approximately 80 ppm, approximately 85 ppm, approximately 90 ppm, approximately 95 ppm, approximately 100 ppm, approximately 120 ppm, approximately 140 ppm million, about 160 ppm, about 180 ppm, about 199.8 ppm, about 200 ppm, or any range including and / or between any two of these values.

[0040] Lignocellulosic materials have also been previously described. In the method, the lignocellulosic material is preferably bleached kraft pulp, more preferably fluff pulp, which contains bleached kraft fiber. The bleached kraft fiber / stock may have any one or more of the features described for the bleached kraft fluff pulp technology of the present invention (e.g., weighted average fiber length of at least about 2 mm, copper number less than about 7, carboxyl content greater than about 3.5 meq / 100 g; an ISO brightness of at least 80 and a viscosity of about 2 cps to about 9 cps, or a combination of any two or more of these), as well as any range described herein.

[0041] You can also add an iron salt with a copper salt, for example, from about 25 ppm to about 175 ppm iron salt. Iron salts have been described previously, and the term "iron salt" should mean either one iron salt, a mixture of any two or more iron salts, a hydrate of any one or more of the foregoing, or a combination of any two or more of them. The amount of iron salt added can be about 25 ppm, about 26 ppm, about 28 ppm, about 30 ppm, about 32 ppm, about 34 ppm, about 36 ppm, about 38 ppm, about 40 ppm, about 42 ppm, about 44 ppm, about 46 ppm, about 48 ppm, about 50 ppm, about 55 ppm, about 60 ppm million, about 65 ppm, about 70 ppm, about 75 ppm, about 80 ppm, about 85 ppm, about 90 ppm, about 95 ppm, about 100 ppm, approximately 120 ppm, approximately 140 h ppm, about 160 ppm, about 165 ppm, about 170 ppm, about 175 ppm, or any range including and / or between any two of these values. In the process, the weight ratio of iron salt to copper salt is at most about 10: 1. By the phrase "at most about 10: 1" is meant that no greater ratio of iron salts to copper salts is included, such as 11: 1, but does not include a range where iron is not included, since then there will be no ratio at all. The weight ratio of iron salts to copper salts can be about 10: 1, about 9: 1, about 8: 1, about 7: 1, about 6: 1, about 5: 1, about 4: 1, about 3: 1, about 2: 1, approximately 1: 1, approximately 1: 2, approximately 1: 3, approximately 1: 4, approximately 1: 5, approximately 1: 6, approximately 1: 7, approximately 1: 8, approximately 1: 9, approximately 1:10 or any range including and / or between any two of these values.

[0042] For example, the method may include treating a first lignocellulosic material by adding from about 3.5 ppm to about 200 ppm copper salt and from about 25 ppm to about 175 ppm iron salt at a pH of about 1 to about 9 to form a second lignocellulosic material.

[0043] In any embodiment of this document, the copper salt (and, where applicable, the iron salt) can be added as an aqueous solution. In such embodiments, the method may include treating a first lignocellulosic material by adding an aqueous solution of a copper salt (and, where applicable, an iron salt) at a pH of from about 1 to about 9 to provide a wetted lignocellulosic material and drying the wetted lignocellulosic material to provide a second lignocellulosic material; wherein the second lignocellulosic material contains from about 0.5 ppm to about 200 ppm copper salt (or any previously described range) and, if an iron salt is included, from about 25 ppm to about 175 ppm iron salt ( or any previously described range). Also, the method may include drying the wetted lignocellulosic material followed by fluffing to obtain a second lignocellulosic material.

[0044] In any embodiment of the present document, the second lignocellulosic material may have any one or more of the features previously described for fluff pulp (e.g., weighted average length of at least about 2 mm, copper number less than about 7, carboxyl group content greater than about 3.5 meq / 100 g; an ISO brightness of at least 80 and a viscosity of about 2 cps to about 9 cps, or a combination of any two or more of these), as well as any range described herein. In any embodiment of the present invention, and as previously discussed for fluff pulp, the treated lignocellulosic material may have a copper ion content of from about 0.2 ppm to about 50 ppm, based on the weight of the treated lignocellulosic material, or any range of copper ion content. described in this document. In any embodiment of the present invention, and as previously discussed for fluff pulp, the treated lignocellulosic material may have an iron ion content of from about 0.2 ppm to about 50 ppm, based on the weight of the treated lignocellulosic material.

[0045] The treated lignocellulosic material or second lignocellulosic material can be subjected to a number of subsequent treatments to further modify the properties of the material. For example, in any embodiment of the present document, the treated lignocellulosic material or second lignocellulosic material can be treated with a cationic agent that (without limitation to any theory) is believed to bind the reducing functional groups of the treated materials. Suitable cationic material can vary widely and include, but is not limited to, cationic nitrogen-containing polymers such as polyamines, 1-ethyl-3- (3-dimethylaminopropyl) -carbodiimide hydrochloride (EDC), hexadimethrine bromide, polyethyleneimines (linear and / or branched) , copolymers of diallyldimethylammonium chloride (DADMAC), copolymers of vinylpyrrolidone (VP) with quaternized diethylaminoethylmethacrylate (DEAMEMA), polyamides, cationic polyurethane latex, cationic polyvinyl alcohol, polyalkylamino polyamines, copolymethylamino copolymers ] dichlorides, high charge density polyvinylamine, polyallylamine (RAS), poly (hexamethylenebiguanide hydrochloride) (PHMB), polyamidoamine (or polyethyleneimine); cationic metal ions such as water-soluble aluminum salts, calcium salts and / or zirconium salts; and cationic dendrimers such as (polyamidoamine) dendrimers (PAMAM dendrimers) with amine surface groups and polypropyleneimine dendrimers with amine surface groups. Without wishing to be bound by theory, it is believed that treatment with such cationic materials can modify properties such as increasing stock, which is desirable for fine paper, board, fabric, towels and absorbent products, while maintaining good strength and reduced water retention capacity (WRV) and increased friability.

[0046] The treated lignocellulosic material or second lignocellulosic material can be treated with micro- or nanoparticle metal oxides such as alumina, titanium oxide, zinc oxide and / or silica, where such materials are retained by the treated lignocellulosic material to modify properties such as dye fixation, color fixation, optical brighteners fixation, printability and / or odor control properties. The treated lignocellulosic material, or the second lignocellulosic material, can be treated with a crosslinking material in paper making or fibrous mesh formation. Typical crosslinking materials include water-dispersible or water-soluble bi- or polyfunctional carbodiimide and / or polycarbodiimide, such as 1,6-hexamethylenebis (ethylcarbodiimide); 1,8-octamethylenebis (ethylcarbodiimide); 1,10-decamethylenebis (ethylcarbodiimide); 1,12-dodecamethylenebis (ethylcarbodiimide); PEG bis (propyl (ethylcarbodiimide)); 2,2'-dithioethylbis (ethylcarbodiimide); 1,1'-dithio-p-phenylenebis (ethylcarbodiimide) and 1,1'-dithio-m-phenylenebis (ethylcarbodiimide). Bi- or polyfunctional carbodiimide groups react with reducing functional groups of the treated lignocellulosic material (or second lignocellulosic material) and crosslink the fibers of the material within the structure of the paper or fiber mesh.

[0047] The treated lignocellulosic material or second lignocellulosic material can be used for conventional purposes in situ or after isolation using conventional product isolation techniques. For example, the treated lignocellulosic material or second lignocellulosic material can be used to form paper or paperboard substrates or webs. Methods and apparatus for producing a substrate formed from lignocellulosic fibers are well known in the paper and paperboard industry. See, e.g., «Handbook For Pulp & Paper Technologies )), 2 ^{nd Edition, GA Smook, Angus Wilde} Publications ( 1992) and references cited therein. Any conventional method and device can be used. Preferably, such a method for using the treated lignocellulosic material (or second lignocellulosic material) comprises: a) depositing an aqueous suspension of lignocellulosic fibers from the treated lignocellulosic material onto a forming yarn of a paper machine to form a wet paper or paperboard web; b) drying the wet paper or paperboard web to obtain a dried paper or paperboard web; and c) calendering the dried paper or paperboard web. In addition, additional steps known to those skilled in the art can be used; for example, the step of coating one or more surfaces of the dried paper or paperboard web with a coating that contains a binder containing a dispersing pigment and / or treating the dried paper or paperboard on a gluing press with an adhesive such as starch.

[0048] The treated lignocellulosic material or second lignocellulosic material can be used to make absorbent articles, such as diapers, fabrics, towels and / or personal care products, using conventional methods. Such products and their methods of making are known to those skilled in the art. See, for example, US Pat. Nos. 6,063,982 and 5,766,159 (both of which are incorporated herein by reference, excluding any portion (s) that might conflict with the teachings of the present invention) and the references described there. Processed lignocellulosic kraft stock (which optionally contains treated kraft fibers) can be used to make impregnated kraft paper. Impregnated kraft paper is a sheet of paper made from unbleached kraft paper (usually a mixture of mainly hardwood and some softwood, such as swamp pine) that is used as a substrate for impregnation and curing with resinous polymers. Impregnated kraft paper is used as building material for homes and offices such as kitchen countertops. An advantageous property of impregnated kraft paper is to control the rate of penetration of a liquid (typically a polymer resin solution) into the sheet while maintaining the porosity and density of the paper. All of the hardwood kraft fibers in the impregnated sheet can be replaced with softwoods such as swamp pine kraft pulp (pine kraft pulp for linerboard) processed by the methods of any embodiment of this document to provide impregnated kraft paper with good liquid transfer properties.

Examples of

[0049] The examples herein are presented to illustrate the advantages of the technology of the present invention and to further assist a person skilled in the art in making or using the methods of the technology of the present invention. The examples herein are also presented to more fully illustrate the preferred aspects of the technology of the present invention. The examples should not in any way be construed as limiting the scope of the technology of the present invention. Examples may include or contain any variations, embodiments, or aspects of the technology of the present invention described above. Each variant, embodiment, or aspect of the technology of the present invention described above may also further include or comprise variants of any or all other embodiments, embodiments, or aspects of the technology of the present invention.

[0050] Example 1. Technique for measuring the inhibitory properties of fluff pulp without SAP in relation to ammonia

[0051] A sheet of fluff pulp was cut into 2 inch strips and defibrated using a Kamas H01 laboratory hammer mill. The pulp was formed into a disc with a diameter of 50 mm using a wadding apparatus for air-dry spinning. Each disc was prepared from 4 g of fluff, unless otherwise indicated. The disc was compressed on a Carver press to a density of approximately 0.15 g / cm ³ . Two pressed discs were placed in a sealed 1 L bottle. 40 ml of a freshly prepared 1.0% urease solution (urease from Canavalia ensiformis (Jack Bean), purchased from Sigma) in synthetic urea (RICCA Chemical Company) was added to each 4 gram disc and the bottle was closed. After 8 hours, a Dräger tube was used to detect the headspace ammonia concentration in the bottle. As provided by this procedure, the lower the ammonia concentration, the better the inhibiting effect of fluff pulp on ammonia.

[0052] Example 2. Technique for measuring the inhibitory properties of fluff pulp with SAP in relation to ammonia

[0053] A sheet of fluff pulp was cut into 2 inch strips and defibrated using a Kamas H01 laboratory hammer mill. The pulp was mixed with SAP to a total weight of 10 g. For example, if a disc with 10% SAP is required, then 9 g of fluff was mixed with 1 g of SAP. The SAP used is HySorb® 9400 (BASF) unless otherwise noted. The mixture of pulp and SAP was then fed to a wadding apparatus by air dry spinning to form a 100 cm ² circular disc. The disc was compressed to about 0.15 g / cm ³ using a Carver press. The disc was placed in a 7 L sealed container. 100 ml of 1.0% urease solution (described in example 1) was added to the disk and the container was closed. After 8 hours, a Dräger tube was used to detect the headspace ammonia concentration in the container.

[0054] Example 3

[0055] The pulp was collected after the first clarification step (D ₁ ) with chlorine dioxide in the commercial bleaching sequence D ₀ E _op D ₁ D ₂ and had a viscosity of 16.5 cps. This pulp was treated in an acid bleaching step containing various types and amounts of metal salts as indicated in Table 1. Each treatment used 100 g dry pulp at a concentration of 10% (i.e. 10 wt% cellulose in solution) and 3% peroxide hydrogen (i.e. 3 wt.% based on cellolose) at a temperature of 85 ° C for a period of 130 minutes.

[0056] After processing, the pulps were washed with 4 L of deionized water and thickened to approximately 20% solids. Thickened pulp was then diluted to a concentration of about 1% DI water and formed into 750 g / ^m2 handsheets in the form of 8 inches by 8 inches. The wet cellulosic sheet was pressed between blotting paper to remove excess liquid and then dried in a rotary drum dryer at 250 ° F. The ammonia inhibition properties of the dried sheet were then tested with and without SAP as described in Examples 1 and 2. As shown in Table 1, using at most 25 ppm CuSO ₄ in combination with FeSO ₄ had a pronounced inhibitory effect on the formation of ammonia: the inhibition of ammonia when SAP was not included, was about 50% (100% - (3 ppm NH _3/6 ppm NH ₃ X 100%) = 50%) when 25 ppm CuSO ₄ was used in acidic peroxide bleaching relative to input 1. In addition, when 50 ppm CuSO _{4 was} used in combination with 55 ppm FeSO ₄ , there was 100% ammonia inhibition when SAP was not included and about 82% ammonia inhibition when SAP included.

[0057] Example 4

[0058] The conditions for industrial production were carried out in the mill of International Paper's Riegelwood, NC. This mill bleaches softwood kraft using the bleaching sequence D ₀ E _op D ₁ D ₂ . Stage D _{2 was} changed to obtain a low viscosity mass using 3% hydrogen peroxide and metal salt, where the composition and content of the metal salt were changed. The first mass (item 1, table 2) was obtained using 150 ppm FeSO ₄ as the only metal salt. The second mass (item 2, table 2) was obtained using 125 ppm FeSO ₄ and 25 ppm CuSO ₄ . Both of these sets of reaction conditions produced low viscosity masses.

[0059] Each pulp was then made into a fluff pulp sheet on a table type paper machine with cylindrical steam-heated drying drums. Samples of each dried sheet were then taken and tested for ammonia inhibition as described in Examples 1 and 2. As shown in Table 2, already 25 ppm CuSO ₄ used in the acidic hydrogen peroxide bleaching step had a clear inhibitory effect on ammonia formation. This result was found for disks received with and without SAP.

[0060] Example 5

[0061] The fluff pulp sheet (RW SuperSoft® Plus; commercially obtained from International Paper) was immersed in a bath of deionized water at room temperature (72 ° F) per minute with increasing concentrations of copper sulfate pentahydrate (II) (CuSO ₄ ^⋅ 5H ₂ O). After the impregnation procedure, the cellulosic sheet was pressed between blotting paper to remove excess liquid, and the sheet was dried in a rotary drum dryer at 250 ° F.. The dried sheet was then tested for ammonia inhibition as described in Examples 1 and 2, where Table 3 shows the results of these tests. Already 1.0 ppm Cu ²⁺ had a clear inhibitory effect on ammonia formation.

[00621 Example 6

[0063] In the fluff pulp sheet (RW SuperSoft® Plus; commercially obtained from International Paper) was sprayed different aqueous solutions containing deionized water, and various concentrations of copper sulfate pentahydrate (II) (CuSO ₄ 5H ₂ ^O.). Spraying the fluff pulp on the sheet was continued until it became visibly wet. After the spraying procedure, each cellulosic sheet was pressed between blotting paper to remove excess liquid, and the sheet was dried in a rotary drum dryer at 250 ° F.. Each dried leaf was then tested for ammonia inhibition as described in Example 1, where Table 4 shows the results of these tests. Already 0.7 ppm Cu ²⁺ had a clear inhibitory effect on ammonia formation.

[0064] The technology of the present invention should not be limited to the specific figures and examples described herein, which are intended only to illustrate certain aspects of the technology of the present invention. Many modifications and changes to this technology of the present invention can be made without deviating from its scope and spirit, which will be obvious to specialists in this field. Functionally equivalent methods within the scope of the technology of the present invention, in addition to those set forth herein, will be apparent to those skilled in the art from the descriptions above. Such modifications and variations should fall within the scope of the appended claims. It should be understood that the technology of the present invention is not limited to specific methods, reagents, compounds, compositions or labeled compounds, which may of course vary. It should also be understood that the terminology used herein is presented only for the purpose of describing specific aspects and is not intended to be limiting.

[0065] The embodiments illustratively described herein may be suitably practiced in the absence of any element or elements, limitation or limitation not specifically disclosed herein. Thus, for example, the terms “comprising”, “including”, “having”, etc., should be read in an expansive sense and without limitation. In addition, the terms and expressions used in this document have been used as terms of description and not limitation, and it makes no sense to use such terms and expressions to exclude any equivalents of the features shown and described, or parts thereof, but it is recognized that various modifications are possible. in the amount of the declared technology. In addition, the phrase "consisting mainly of" will be understood to include those elements that are specifically indicated and those additional elements that do not physically affect the basic and new characteristics of the claimed technology. The phrase "consisting of" excludes any unspecified element.

[0066] In addition, if features or aspects of the disclosure are described in relation to Markush groups, those skilled in the art will recognize that the disclosure is also described in relation to any individual member or subgroup of members of the Markush group. Each of the narrower species and subgeneric groupings falling within the general disclosure also form part of the present invention. This includes a general description of the present invention, provided or negatively constrained to remove any object from the genus, regardless of whether the excluded material has been specifically indicated herein or not.

[0067] All publications, patent applications, issued patents, and other documents (eg, journals, articles, and / or textbooks) referred to in this description are incorporated herein by reference, as if each individual publication, patent application issued the patent and other document has been expressly and separately indicated as incorporated by reference in its entirety. Definitions that are contained in text incorporated by reference are excluded to the extent that they conflict with the definitions in this disclosure.

[0068] Other embodiments are set forth in the following claims, together with the full scope of equivalents to which such claims are entitled.

Claims (53)

1. Fluff pulp containing: bleached kraft fiber having a weighted average fiber length of at least about 2 mm; copper number less than about 7; the content of carboxyl groups is more than about 3.5 meq / 100 g; an ISO whiteness of at least 80 and viscosity from about 2 cps to about 9 cps; and copper ion contents of from about 0.2 ppm to about 50 ppm, based on the weight of the bleached kraft fiber. 2. The cellulose fluff according to claim 1, wherein the copper ions from the contained copper ions form a copper (I) salt, a copper (II) salt, hydrates thereof, or a combination of any two or more of them. 3. Fluff pulp according to claim 1 or 2, in which the copper ions from the contained copper ions form one or more of elemental copper, copper (I) chloride, copper (I) oxide, copper (I) sulfate, copper (II) carbonate , copper (II) chloride, copper (II) phosphate, copper (II) nitrate, copper (II) perchlorate, copper (II) phosphate, copper (II) sulfate, copper (II) tetrafluoroborate and copper (II) triflate. 4. Fluff pulp according to any one of paragraphs. 1-3, and the cellulose fluff additionally contains iron ions. 5. The cellulose fluff of claim 4, wherein the fluff has an iron ion content of from about 0.2 ppm to about 50 ppm, based on the weight of the bleached kraft fiber. 6. Fluff pulp according to any one of paragraphs. 1-5, wherein the cellulose fluff does not contain superabsorbent polymer (SAP). 7. A method of obtaining fluff pulp, providing: treating the lignocellulosic material by adding, based on the weight of the lignocellulosic material, from about 50 ppm to about 200 ppm catalyst consisting of a combination of copper and iron or their salts, in the presence of about 0.5% to about 5% oxidizing means, based on the weight of the lignocellulosic material, for obtaining the treated lignocellulosic material; moreover the weight ratio of iron and iron salts to copper and copper salts is at most about 10: 1; the treated lignocellulosic material has a viscosity of about 2 cps to about 6 cps; and the treated lignocellulosic material has at least 50% greater inhibitory effect on ammonia formation than the second treated lignocellulosic material formed by the same method in the absence of copper. 8. A method according to claim 7, wherein the copper or its salts are composed of one or more of elemental copper (Cu °), a copper (I) salt and a copper (II) salt. 9. The method according to claim 7 or 8, in which copper or its salts consist of elemental copper, copper (I) chloride, copper (I) oxide, copper (I) sulfate, copper (II) carbonate, copper (II) chloride , copper (II) phosphate, copper (II) nitrate, copper (II) perchlorate, copper (II) phosphate, copper (II) sulfate, copper (II) tetrafluoroborate and copper (II) triflate, their hydrates or combinations of any two or more of them. 10. The method according to any one of claims. 7-9, in which iron or its salts are composed of elemental iron, ferrous salts (Fe ²⁺ ), ferric salts (Fe ³⁺ ), their hydrates, or combinations of any two or more of them. 11. The method according to any one of claims. 7-10, in which iron or its salts consist of elemental iron, ferrous sulfate, ferrous chloride, double ferrous-ammonium sulfate, ferric chloride, double ferric-ammonium sulfate, double ferric-ammonium citrate, their hydrates or combinations of any two or more of them. 12. The method according to any one of claims. 7-11, wherein the weight ratio of iron and iron salts to copper and copper salts is from about 10: 1 to about 1:10. 13. The method according to any one of claims. 7-11 in which the weight ratio of iron and iron salts to copper and copper salts is from about 3: 1 to about 1: 3. 14. The method according to any one of claims. 7-13, in which the oxidizing agent contains hydrogen peroxide. 15. The method according to any one of claims. 7-14, the method comprising a multi-stage bleaching process, the treatment step being the final bleaching stage in the multi-stage bleaching process. 16. The method according to any one of claims. 7-15, in which the treated lignocellulosic material does not contain superabsorbent polymer (SAP). 17. A method of obtaining fluff pulp, providing: treating the lignocellulosic kraft mass by adding, based on the weight of the lignocellulosic material, from about 50 ppm to about 200 ppm catalyst consisting of a combination of copper and iron or their salts, in the presence of about 0.5% to about 5 % oxidizing agent based on the weight of the lignocellulosic material at acidic pH to obtain the treated lignocellulosic material; moreover the weight ratio of added iron and iron salts to copper and copper salts is at most 10: 1; the treated lignocellulosic material has a viscosity of about 2 cps to about 6 cps; and the treated lignocellulosic material has at least 50% greater inhibitory effect on ammonia formation than the second treated lignocellulosic material formed by the same method in the absence of copper. 18. The method according to claim 17, in which copper or its salts consist of elemental copper, copper (I) chloride, copper (I) oxide, copper (I) sulfate, copper (II) carbonate, copper (II) chloride, phosphate copper (II), copper (II) nitrate, copper (II) perchlorate, copper (II) phosphate, copper (II) sulfate, copper (II) tetrafluoroborate and copper (II) triflate, their hydrates or combinations of any two or more of them. 19. The method according to claim 17 or 18, in which the iron or its salts consist of elemental iron, ferrous sulfate, ferrous chloride, double ferrous ammonium sulfate, ferric chloride, double ferric ammonium sulfate, double ferric citrate iron-ammonium, their hydrates, or combinations of any two or more of them. 20. The method according to any one of claims. 17-19, in which the weight ratio of iron and iron salts to copper and copper salts is from about 10: 1 to about 1:10. 21. The method according to any one of paragraphs. 17-20, in which the oxidizing agent contains hydrogen peroxide. 22. A method of obtaining fluff pulp, providing: treating the lignocellulosic kraft mass by adding, based on the weight of the lignocellulosic material, from about 50 ppm to about 200 ppm catalyst consisting of a combination of copper and iron or their salts, in the presence of about 0.5% to about 5 % oxidizing agent, based on the weight of the lignocellulosic material, at a pH of about 2.5 to about 5 to provide a treated lignocellulosic material; moreover lignocellulosic kraft mass is in aqueous solution in an amount of about 8 wt. % to about 12 wt. % lignocellulose kraft mass, taking into account water in solution; the weight ratio of iron and iron salts to copper and copper salts is from about 8: 1 to about 1: 8; the treated lignocellulosic material has a viscosity of about 3 cps to about 5 cps; and the treated lignocellulosic material has at least 50% greater inhibitory effect on ammonia formation than the second treated lignocellulosic material formed by the same method in the absence of copper. 23. A method according to claim 22, wherein the method comprises a multi-stage bleaching process, the processing step being the final bleaching stage in the multi-stage bleaching process. 24. The method of claim 22 or 23, wherein the treated lignocellulosic material does not contain a superabsorbent polymer (SAP). 25. A method for improving the properties of fluff pulp in relation to the ability to eliminate unpleasant odor, and the method includes: treating the first lignocellulosic material by adding about 3.5 ppm to about 200 ppm copper salt and about 25 ppm to about 175 ppm iron salt at a pH of about 1 to about 9 to provide a second lignocellulosic material ; moreover the weight ratio of iron salt to copper salt is from about 8: 1 to about 1: 1; the dry second lignocellulosic material has at least 50% greater inhibitory effect on ammonia formation than the dry first lignocellulosic material. 26. The method of claim 25, wherein the second lignocellulosic material does not contain a superabsorbent polymer (SAP).